Tattooed Joseph Gordon-Levitt gives a fiery performance as a heavy-metal angel in "Hesher."

And now a reading from the book of Megadeth.

In a more ideal world, the heavy-metal angel played by Joseph Gordon- Levitt in “Hesher” would meet the simpering wuss he played in “(500) Days of Summer” and soundly horsewhip the latter with those twee parentheses that set off the 500 like a little picket fence.

In the earlier movie, cute lovers would achieve movie cuteness. Maybe they’d sneak into a neighbor’s backyard to use his pool! In this delectably anarchic black comedy, Hesher does use a pool uninvited. But he has the wit to fill the pool with lawn furniture and set the diving board on fire.

Hesher, violent of hair, bare of chest, black of jeans and sporting a large middle finger tattoo on his back (in case you get behind him), is a burnout who appears in the life of a miserable young boy (Devin Brochu) who is missing his mom. The boy is living in the past. His father (Rainn Wilson), a crumpled ex-man in sweatpants, isn’t living at all. Only the boy’s sweetly weird grandmother (Piper Laurie) appreciates the importance of the present, although she is aided by what she calls “medical cigarettes to help with the nausea.”

Sharing in the general gloom is a 15-hour-a-week grocery-store cashier (Natalie Portman) who can’t afford the cost of a parking ticket. After she rescues the boy, T.J., from a bully who forces him to dine on a used urinal cake, T.J. launches a one-man charity drive on her behalf: “Nicole’s parking ticket fund,” he writes on an envelope. It is perhaps the only problem in the movie that can really be solved.

“Hesher” is a refreshingly original debut directed and co-written by Spencer Susser, who correctly calls his hero a “heavy-metal Mary Poppins.” It embraces some indie-movie clichés but mainly to rebuke them. Unlike many films that hope to be called black comedy, it does not skimp on either the black or the comedy. This touching piece of advice is given in the presence of Grandma: “You should walk with your grandma. So she doesn’t get raped.” There are assaults, arson and theft of a porn channel, all of it stupid and brilliant.

Real-life Heshers — seen snickering six inches off the boundary of high school, smoking cigarettes and smashing bottles — are best avoided during that brief period between the full flowering of their antisocial skills and their inevitable departure to prison or the military or maybe the grave. The screen Hesher, though, is a cosmic clown, an imp of the perverse on a mission of the inappropriate.

The movie does turn sentimental in the end, yet this, too, is appropriately metal (it comes with a parable about a missing testicle sacrificed to the imperative of home explosives). And it’s no secret that the metal band’s best number is often the big, weepy ballad — Motley Crue’s “Home Sweet Home” or Extreme’s “More Than Words.”

Sometimes the only response to despair and cruelty, Hesher figures, is to make things go boom. In some bizarro Book of Job, I’d like to see the poor slob fight back as colorfully as Hesher: It wouldn’t accomplish anything, but it would at least show some freaking spirit.